The disclosure relates to position measurement for repair and maintenance management of structures. More particularly, the disclosure relates to systems and methods for non-contact non-destructive measurement and inspection of structures.
When repair work is required on a structure, it may be necessary to take into account the size, shape and location of previous damage and/or repairs for optimum repair of the structure. Photographs of the previous damage and/or repair may be made but may not be precisely located or sized on the structure or may not be useful for future repair planning. During the analysis of a damage/repair site (i.e., a location of interest), it may be desirable to obtain measurement information without contacting the target object. Due to accessibility and/or contact constraints, it may be difficult to reach the location of interest to obtain position measurements. Therefore it is advantageous for a local positioning system to be able to take measurements without contacting the target object and from moderate to large distances from the target object. Local positioning systems capable of stand-off measurement of a target object may utilize acoustic, laser-based, magnetic, RFID, GPS, and motion capture-based systems.
Finding and accurately measuring the locations of potential damage on a structure such as a storage tank or on a large vehicle such as a commercial airplane can be a laborious task. An efficient and automated process for addressing this problem would be valuable to many organizations involved in building and maintaining large vehicles and structures.
Prior inspection processes required inspection experts to be present with the measurement hardware at the site of the airplane (or other target object) being inspected. In accordance with that process, the inspection expert is required to travel to the inspection site, set up the equipment, and then perform the inspection. The end-to-end time requirement could be several days, depending on how far the expert had to travel.
Other semi-automated systems allowed remote operation of stationary measurement hardware, but still required an on-site assistant in order to set up and move the measurement instruments into position. One stand-off inspection system combines a local positioning system (LPS) with a nondestructive inspection (NDI) method to replace inspector's manual labor, increase the inspection rate, and find much smaller cracks than what can be seen visually, without physically touching the large target object. Another inspection system combines a stand-off local positioning system positioned adjacent to a large target object (i.e., at the inspection site) with an NDI scanner mounted to the target object. In accordance with the teachings of U.S. Pat. No. 9,182,487, the system can be configured and programmed with remotely operated hardware and software components to enable data collection by an expert NDI analyst from an off-site operations center, with the only on-site assistance coming from non-expert support personnel to setup the local positioning system and NDI scanning hardware.
Furthermore, an NDI scanner mounted to a target object may be more difficult to use due to the contact between the sensor and the surface being inspected. For example, in-service NDI scans can be challenging because there any many structural elements (e.g., lightning protection, stiffeners, ramped back surfaces, etc.) that can add to the scan complexity. This can lead to extended inspection times, mistakes, or further inspections in order to increase the clarity of the results.
It would be advantageous if a remotely operable mobile system for NDI of a large target object, such as a storage tank or an airplane, could be set up at the inspection site with minimal on-site personnel assistance. In addition, it would be advantageous to employ a system for measurement and inspection which did not require contact with the target object. Accordingly, a mobile telepresence system capable of performing stand-off measurement and/or inspection of a large target object would be advantageous.